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United States Patent | 5,504,857 |
Baird ,   et al. | April 2, 1996 |
A computer implemented method for robustly copying pages to system managed storage in order to maintain data in a consistent state and in order to provide continuous access availability of the pages to executing applications. The method achieves data consistency by atomically shadow copying application referenced pages and amending directories in a failure independent medium on (1) an access path interrupt as well as on (2) a page update basis. Availability is enhanced by duplexing the pages and directories as part of the atomic shadow copying step.
Inventors: | Baird; Robert (San Jose, CA); Bozman; Gerald P. (Oakland, NJ); Eisenberger; George (White Plains, NY); Kamerman; Albert (Pound Ridge, NY); Lett; Alexander S. (Mahopac, NY); McAssey; John J. (Monroe, NY); Myers; James J. (San Francisco, CA); Tetzlaff; William H. (Mount Kisco, CA); Wang; Pong-sheng (San Jose, CA) |
Assignee: | International Business Machines (Armonk, NY) |
Appl. No.: | 026278 |
Filed: | March 4, 1993 |
Current U.S. Class: | 714/6 |
Intern'l Class: | G06F 011/00 |
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Bozman et al, "A Method for Managing a Data Cache Using Virtual External Storage Addresses as Argument". D. J. Haderle et al, "Method for Managing Subpage Concurrency Control and Partial Transaction-Oriented System of the Write Ahead Logging Type". Refer to copending patent application Ser. No. 07/493,581 IBM publication GC28-1150, "MVS/Extended Architecture System Programming Library: System Macros and Facilities". vol. 1. Refer to Amdahl et al, U.S. Pat. No. 3,400,371, "Data Processing System", issued on Sep. 3, 1968, Ser. No. 357,372. |